“Wash your hands!” How many times did you hear this as a child, or tell your own children? One of the simplest ways to stay healthy is to practice good hand hygiene. In fact, according to the Centers for Disease Control and Prevention, hand hygiene is the single most important step health workers can take to prevent the spread of infection.

It seems to follow that the best way to get rid of germs is to use one of the myriad antibacterial hand soaps on the market. Not necessarily, says Athena Kourtis, SPH ’03 (MPH), a pediatric infectious disease specialist at the CDC and author of Keeping Your Child Healthy in a Germ-Filled World (Johns Hopkins University Press, 2011). As far as household use goes, there have been no studies proving that antibacterial soaps and cleaning products prevent infection better than plain soap, Kourtis says. “And that’s probably because most of the common infections in households are viral infections, and viruses will not be killed by antibacterial soaps.” These products might be doing more harm than good. Because antibacterial soaps are actually antibiotic, their overuse might promote the development of antibiotic-resistant germs—germs that could be transmitted to anyone. “Particularly with children who share toys and other objects in day care and school, where it has been shown that if one child carries in their throat, say, a germ that’s resistant to amoxicillin, then you found that even other children in day care who have not been exposed to the particular antibiotic also carry the resistant germ. So this is a problem that easily spreads across a community,” says Kourtis. “And there are other mechanisms as well. It’s not just person-to-person contact. These substances get into the water, into sewage systems, into the ground. It’s a wider community problem.”

Antibacterial cleaning products contain chemicals like triclosan and triclocarban, which kill bacteria. Plain soap, by comparison, is low-tech. It works by binding to dirt or other particles, making it easy to rinse these particles off with water without releasing problematic chemicals into the environment. (There has been concern recently that triclosan might become toxic when it comes into contact with sunlight, and triclocarban is a suspected carcinogen.) Insituations where soap and water aren’t available, Kourtis advocates use of hand sanitizers. Many of these products contain alcohol, which makes them effective against bacteria and a variety of other microorganisms, including fungi and certain viruses such as influenza. Because sanitizers don’t contain antimicrobial ingredients like triclosan, they don’t contribute to antibiotic resistance, making them the CDC’s recommended choice for use by health care workers.